Objectives: Changes of 8 putative periodontal pathogens in Chinese chronic periodontitis patients 1 year after non-surgical therapy as detected by polymerase chain reaction (PCR) were investigated. Methods: 13 Chinese patients suffering from moderate to advanced chronic peridontitis were recruited. Full mouth clinical parameters were recorded, and subgingival plaque samples were taken from 2 deepest sites in each quadrant at baseline, 3-, 6- and 12-month. A 16S rRNA gene based PCR method was used to detect 8 putative periodontal pathogens: A. actinomycetemcomitans (A.a.), T. denticola (T.d.), P. nigrescens (P.n.), E. corrodens (E.c.), P. intermedia (P.i.), P. gingivalis (P.g.), C. rectus (C.r.) and T. forsythensis (T.f.). All sites were treated with conventional non-surgical periodontal therapy. Results: The prevalences of the 8 species at subject level are shown below:
|
|
A.a |
T.d. |
P.n. |
E.c. |
P.i. |
P.g. |
C.r. |
T.f. |
|
Baseline |
56% |
100% |
94% |
100% |
88% |
100% |
100% |
100% |
|
3-month |
15% |
31% |
8% |
31% |
23% |
62% |
77% |
0% |
|
6-month |
15% |
46% |
8% |
8% |
8% |
38% |
46% |
15% |
|
12-month |
8% |
62% |
8% |
92% |
15% |
85% |
100% |
62% |
At baseline, the prevalence of 7 of the 8 putative pathogens were very high (around 90-100% for T.d., P.n., E.c., P.i., P.g., C.r., and T.f.) and 56% for A.a. The prevalence of all these species dropped significantly at 3- and 6-month. However, the prevalence of T.d., E.c., P.g., C.r. and T.f. rebounded to 60-100% at 12-month while A.a., P.n. and P.i. remained at a low level (8-15%). All clinical parameters showed positive improvement after 12 months. Conclusion: Results showed that prevalence of the 8 putative periodontal pathogens in patients with chronic periodontitis treated by non-surgical periodontal therapy could be reduced to a low level after 6 months but the prevalence of some of the species may gradually increased towards the original level after 12 months.